85 lines
2.9 KiB
Python
85 lines
2.9 KiB
Python
"""
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Completer for a regular grammar.
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"""
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from __future__ import unicode_literals
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from prompt_toolkit.completion import Completer, Completion
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from prompt_toolkit.document import Document
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from .compiler import _CompiledGrammar
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__all__ = (
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'GrammarCompleter',
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)
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class GrammarCompleter(Completer):
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"""
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Completer which can be used for autocompletion according to variables in
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the grammar. Each variable can have a different autocompleter.
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:param compiled_grammar: `GrammarCompleter` instance.
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:param completers: `dict` mapping variable names of the grammar to the
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`Completer` instances to be used for each variable.
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"""
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def __init__(self, compiled_grammar, completers):
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assert isinstance(compiled_grammar, _CompiledGrammar)
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assert isinstance(completers, dict)
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self.compiled_grammar = compiled_grammar
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self.completers = completers
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def get_completions(self, document, complete_event):
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m = self.compiled_grammar.match_prefix(document.text_before_cursor)
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if m:
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completions = self._remove_duplicates(
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self._get_completions_for_match(m, complete_event))
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for c in completions:
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yield c
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def _get_completions_for_match(self, match, complete_event):
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"""
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Yield all the possible completions for this input string.
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(The completer assumes that the cursor position was at the end of the
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input string.)
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"""
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for match_variable in match.end_nodes():
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varname = match_variable.varname
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start = match_variable.start
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completer = self.completers.get(varname)
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if completer:
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text = match_variable.value
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# Unwrap text.
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unwrapped_text = self.compiled_grammar.unescape(varname, text)
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# Create a document, for the completions API (text/cursor_position)
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document = Document(unwrapped_text, len(unwrapped_text))
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# Call completer
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for completion in completer.get_completions(document, complete_event):
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new_text = unwrapped_text[:len(text) + completion.start_position] + completion.text
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# Wrap again.
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yield Completion(
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text=self.compiled_grammar.escape(varname, new_text),
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start_position=start - len(match.string),
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display=completion.display,
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display_meta=completion.display_meta)
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def _remove_duplicates(self, items):
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"""
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Remove duplicates, while keeping the order.
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(Sometimes we have duplicates, because the there several matches of the
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same grammar, each yielding similar completions.)
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"""
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result = []
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for i in items:
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if i not in result:
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result.append(i)
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return result
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